What are freeze dryers?
Freeze dryers (lyophilizers) are vacuum dryers used for freeze-drying (sublimation drying, lyophilization). In a freeze dryer, a product to be dried is quickly brought into a frozen state. The water is then removed by sublimation and directly passed from the solid-state (ice) to the vapor state.
Freeze-drying is a process commonly used as a preservation technique in the food and pharmaceutical industry. This drying method is very gentle on the product and ensures that qualities such as organic cell walls, vitamins, flavours, or natural colour are largely retained. Most lyophilizers are built using oil-based vacuum pumps and the lyophilisation process itself is carried out under pressure, consisting of primary and secondary drying. Products dried in a freeze-dryer retain only up to 4% of their water content, which effectively slows down the spoilage process of the dried material and reduces its susceptibility to microbial attack.
It is also used in the treatment of heat-sensitive biological materials such as proteins, hormone solutions, microorganisms, tissues, blood plasma, vaccines, serums, and antidotes, among many other biopharmaceutical applications.
What are the components of a freeze dryer?
Despite the many types of industrial freeze dryers available, they generally have the following basic components:
Drying chamber, usually divided into several levels, where the products are placed.
Vacuum system, provided by a vacuum pump.
The refrigeration system cools the condenser and can be used to freeze the products inside the chamber.
Process condenser, where the sublimated vapours are condensed back to the solid state. It is usually accumulated for removal at the end of the drying cycle.
Control systems include pressure and temperature detectors as basic measurements.
Buy your used freeze dryers from Foeth
At Foeth you will find a selection of used freeze dryers. We only offer used dryers from quality brands. Our internal team of experts also makes sure that each machine is mechanically tested. The advantage of the freeze dryers in the Foeth collection is the high quality of the machines and the adaptation to the freeze-drying process of different products. The machines available include Boc Edwards lyophilizers and Christ lyophilizers. In addition to lyophilizers, autoclaves, filters, compactors,mills or mixers are also available at Foeth.
Contact us about buying an industrial lyophilizer or visit us during working hours at our head office in Barneveld, the Netherlands, and take a look at the equipment you are interested in.